open remote url for unknown attachments (#4941)

closes https://github.com/tuskyapp/Tusky/issues/4729

app/src/main/java/com/keylesspalace/tusky/components/account/media/AccountMediaFragment.kt

@@ -206,7 +206,7 @@ class AccountMediaFragment :
                 }
             }
             Attachment.Type.UNKNOWN -> {
-                context?.openLink(selected.attachment.url)
+                context?.openLink(selected.attachment.unknownUrl)
             }
         }
     }

app/src/main/java/com/keylesspalace/tusky/components/search/fragments/SearchStatusesFragment.kt

@@ -216,7 +216,7 @@ class SearchStatusesFragment : SearchFragment<StatusViewData.Concrete>(), Status
                 }
 
                 Attachment.Type.UNKNOWN -> {
-                    context?.openLink(status.attachments[attachmentIndex].url)
+                    context?.openLink(status.attachments[attachmentIndex].unknownUrl)
                 }
             }
         }

app/src/main/java/com/keylesspalace/tusky/entity/Attachment.kt

@@ -27,12 +27,18 @@ data class Attachment(
     val url: String,
     // can be null for e.g. audio attachments
     @Json(name = "preview_url") val previewUrl: String? = null,
+    // null when local attachment
+    @Json(name = "remote_url") val remoteUrl: String? = null,
     val meta: MetaData? = null,
     val type: Type,
     val description: String? = null,
     val blurhash: String? = null
 ) : Parcelable {
 
+    /** The url to open for attachments of unknown type */
+    val unknownUrl: String
+        get() = remoteUrl ?: url
+
     @JsonClass(generateAdapter = false)
     enum class Type {
         @Json(name = "image")

app/src/main/java/com/keylesspalace/tusky/fragment/SFragment.kt

@@ -414,7 +414,7 @@ abstract class SFragment(@LayoutRes contentLayoutId: Int) : Fragment(contentLayo
             }
 
             Attachment.Type.UNKNOWN -> {
-                requireContext().openLink(attachment.url)
+                requireContext().openLink(attachment.unknownUrl)
             }
         }
     }